Firefox is unusable on Linux. Way too slow. But Brave browser is very snappy. It's the fastest chrome fork, and has great features, like vertical tabs, which have become essential to me.
That may be true for you, but not in general. Perhaps there's something about your system configuration that it doesn't handle well.
I am now using screen mirroring software "moonlight" to mirror my PC to the TV pi. I find people who watch ads weak minded apologists. Which is also the reason I will never again use Chrome.
Maybe it's just because I live far away from host servers that aren't from local companies, but real world latency between your machine and the web server is IMO more important than the browser loading a page 200ms faster than another.
I also use Microsoft Edge on Linux for Teams video calls and can't say that I notice an appreciable difference in performance.
That being said, I don't believe this kind of performance is the deciding factor in choosing your web browser any more. All of them are doing at least "Okay" in browsing the web. Other things seem to be more important, at least to me. For example, Firefox (and Mozilla) are not without faults, but they surely are one of the few obstacles remaining to prevent a Chromium monoculture and a fall-back into IE4 times.
All Mozilla need do is fix the longstanding performance issues and they'll win me back.
Keep in mind you also need to have the intel-media-driver installed (for Broadwell+)
Firefox on my Intel iGPU + Nvidia dGPU likes to pretend the iGPU doesn't exist. Very annoying but I've given up on trying to get it to work on desktop. Chrome seems to do a lot better for somme reason.
Regardless which is my main browser, I have to keep both around, because they have different bugs, so there are rare cases with some sites that work well only with one of them.
A few months ago something happened with Chrome, which abruptly (after a version upgrade) has begun to start only after a very long and annoying delay. Perhaps it attempts to connect to some Internet address blocked by the firewall and it gives up only after a timeout.
In any case, this sudden slowdown of Chrome made me switch back to Firefox as my main browser, which is OK now, because Firefox on Linux has become fast again and it no longer has any noticeable speed difference vs. Chrome. Also some problems that Firefox had when playing YouTube videos have been solved.
Your problem may come from your hardware combination together with Wayland/X11.
Firefox isn't unusable on Linux but it should have first class performance and it's a shame it does not.